Physical fitness is a growing concern among people around the world. As a result, activities involving all forms of exercise have become increasingly popular. While many people limit their activities to cardiovascular-type exercises, others have discovered the many benefits of resistance training. Resistance training belongs to the category of exercise systems in which the muscles are worked to partial or total failure against an opposing force, usually gravity or a spring force of some type. Through proper nutrition and rest, the muscles recover such that they are stronger than before the failure was induced. Resistance training in general has been shown to increase lean muscle mass, strengthen joints, improve posture, and raise metabolic levels. It is generally believed that maximum health benefits can be obtained by following an exercise program including a combination of cardiovascular and resistance training. Thus, resistance training should form at least a component of a person's exercise regimen.
Traditionally, people have gone to gyms having weight rooms in order to perform resistance training. These weight rooms are typically equipped with free weights and resistance training machines, such as Nautilus.RTM. equipment. Membership fees to these gyms can be expensive, however. Further, memberships are frequently oversold, resulting in long waits to use equipment. Many people will not tolerate the inconvenience of working out in a gym, while others are intimidated at the idea of working out in the company of strangers.
The inconvenience and expense of exercising in a gym has led to the proliferation of products designed to provide resistance training capability in the home. These products range from large machines, such as universal gym machines, to smaller devices that can be stored in a closet. A universal gym may provide the capability to effectively train every major muscle group, but it is a large device that requires substantial space dedicated for its use. On the other hand, the smaller devices (such as hand grips) generally do not provide an effective, complete workout, as they tend to concentrate on only a single muscle group. In any case, these devices usually must be used at home or in another location; spontaneous use of these devices in public settings is often not practical.
Isometric exercises, however, may be performed virtually anywhere, anytime. Isometric exercises refer generally to resistance training of the muscles by tension, usually provided by working the muscles in opposition to each other or against a substantially immovable object. For example, resistance training of the biceps muscles may be provided by pressing the palms of the hands upward against the underside of a desktop. Likewise, resistance training of the shoulders and chest may be provided by pressing the palms of the hands together and increasing the opposing pressure.
Thus, isometric exercises may be performed at home, in the office, or even while riding public transportation. At home, a person may use opposing muscle groups to provide the necessary tension for a particular exercise. Alternatively, the person may use an object such as a doorway as a base against which to push in order to isometrically exert his muscles. In the office, a desk may be used inconspicuously as a base, or a person may exert opposing muscles against each other while reading or doing other work. Similarly, these exercises may be performed while in a taxi or airplane, or while riding a bus or subway. The flexibility and convenience provided by the very nature of isometric exercises makes it more likely that a person will stick to an exercise plan.
Isometric exercise also allows resistance training to be performed in environments in which other forms of resistance training are impossible. For example, it is entirely impractical to provide resistance training equipment to astronauts stationed in space. Payload restrictions imposed on such missions simply do not allow the stowing of heavy equipment that is not critical to the purpose of the mission. However, isometric exercises may be performed without the use of such equipment, and may be performed without leaving a particular workstation or while complying with other physical restrictions. Isometric exercise is therefore well suited for use by those involved in the space program.
Currently, isometric exercises provide an effective resistance training workout, but provide no indication of the level of work being performed or of the progress made by the person performing the exercises. That is, conventional isometric exercises provide no quantitative measure of the effort exerted by the exerciser. This makes it impossible for the exerciser to set performance goals or to track improvement. Many people require such quantitative data in order to remain motivated to continue with an exercise program.